It is by no means the "disaster" many fans associate it with.
The franchise had survived at least one extremely disappointing entry before, STV:TFF. The problem with NEM was the timing. If NEM had been released at a time when there was enough interest in the franchise to produce another try at bat, such as what TUC was, then NEM wouldn't have been such a disaster.
But there wasn't such an interest, and that's why NEM really was a disaster for the franchise. It was not only the film itself, but also the context in which it was released, that was the problem.
That film being released at that time killed the Prime Universe part of the franchise.
No matter how well NEM was regarded by those who liked it, it just wasn't as good as it needed to be, for the franchise to continue in the Prime Universe.